Universal Distribution of Residual Carriers in Tetrahedrally Coordinated Amorphous Semiconductors

An uncommon electron spin resonance technique is used to show that a universal distribution of residual carriers exists in tetrahedrally coordinated amorphous semiconductors following optical excitation at low temperatures. This universal behavior at long decay times results because statistical fluctuations in the electron and hole densities cannot occur and therefore do not affect the kinetics. This behavior is confirmed for carrier densities between ${10}^{16}$ and ${10}^{17}\mathrm{cm}{}^{-3\mathrm{}}$ and decay times as long as ${10}^4\mathrm{s}$.